Calcaneal Inclination Angle
Also written as: CIA — Calcaneal Inclination Angle
The angle formed between the plantar surface of the calcaneus and the weight-bearing surface, used to quantify rearfoot posture in orthotic assessment.
Full Definition
The calcaneal inclination angle (CIA) is measured on a lateral weight-bearing radiograph as the angle between the inferior border of the calcaneus and the horizontal ground plane. It is a key radiographic metric used to characterise foot arch height and rearfoot alignment. A reduced CIA indicates a flattened arch, while an elevated CIA may suggest pes cavus. Orthotists and podiatrists reference this angle when designing rearfoot posting or arch support features. Editors of clinical orthotic reports must not confuse this with the calcaneal pitch or talar declination angle, which are related but distinct measurements.
Usage
Usage note: CIA is an acceptable abbreviation in clinical radiographic reports; spell out in full on first use. Do not confuse with the unrelated intelligence agency abbreviation in cross-disciplinary documents.
In Context
- "A calcaneal inclination angle of 18° was recorded, consistent with mild arch flattening requiring medial longitudinal arch support." — Orthotic assessment report
- "The treating orthotist noted a reduced CIA on the lateral weight-bearing X-ray and adjusted the rearfoot post accordingly." — Clinical case notes